High-dispersion observations of emission lines in the postnova HR Delphini

Results are reported for analysis of high-resolution line profiles obtained with an echelle spectrograph in the postnova HR Del. The investigated emission lines include H-alpha, the forbidden N II lines at 6548 and 6583 A, and the forbidden O III line at 5007 A. Heliocentric radial velocities of the line components are given along with their normalized relative intensities. The lines are found to have considerable structure which probably arises from condensations in the expanding nebula. It is shown that all the lines contain two major velocity groups, designated as shells A and B, and that shell B is more highly ionized and probably has a higher electron temperature. A large ratio between the intensities of the 6584-A and H-alpha lines is observed in shell A, and it is concluded that this is consistent with a nitrogen excess of a factor of two or more.